The prior art comprises adjustable mouths, known also as universal mouths, which can be adapted to the casing of an archimedes screw, a mixer, blender, extractor, hopper or the like, independently of the angle of inclination at which the conveyor is located in space.
An adjustable mouth of known type comprises a first portion and a second portion which are coupled to one another such that an appendage of the second portion is positioned internally of an appendage of the first portion. The appendage of the first portion is spherical. The appendage of the second portion occupies the whole orifice offered by the appendage of the first portion and adheres to the internal surface of the appendage of the first portion, defining a spherical joint, such that the first and the second portions can be positioned with the longitudinal axes thereof inclined with respect to one another.
The adjustable mouths of known type exhibit some drawbacks.
The two portions which make up the mouth are inserted one into another by permanent plastic deformation. This type of coupling often leads to the definition of surfaces (of the two portions making up the joint) that are not perfectly spherical. This can compromise the seal between the two portions making up the joint. Further, the spherical joint which is created between the two portions always presents a part of surface which is out of reach in a painting operation, i.e. the surmounting surface of the external portion over the internal portion. This non-painted surface is almost always exposed to the outside during the adjustment stage of the joint, for the positioning of the machine in the plant, and thus is not protected in any way from atmospheric agents. The mouth is also not dismountable. A further drawback of adjustable mouths of known type is constituted by their large axial mass, as in order to enable a sufficiently large angle of inclination between the two portions the spherical surfaces have to have a large diameter.
The aim of the present invention is to provide an adjustable mouth which obviates the drawbacks in the adjustable mouths of known type.
With a same maximum reachable inclination, the adjustable mouth of the present invention exhibits a more limited mass with respect to those of the is mouths of known type. The mouth is further easily mountable and dismountable. The smaller overall mass of the mouth enables the archimedes conveyor to be arranged with a smaller inclination with respect to the horizontal, leading to a lower energy consumption in order to activate the screw. The transport of the material is therefore more efficient.